The goal of the Vanderbilt-Meharry HIV Immunopathogenesis core laboratory is to take advantage of recent advances in technology related to the study of immune function in order to advance our understanding of HIV immunopathogenesis. During the first 2 years of the Vanderbilt-Meharry D-CFAR term, the Immunopathogenesis Core (Core D) has supported a multi-disciplinary environment that promotes basic, clinical and translational HIV research. CFAR investigators now have access to state of the art flow cytometry sorting capabilities and advanced fluorescence microscopy in a safe BL3 environment. We have hired experienced staff, and have instituted seamless charge-back mechanisms that allow easy access to our facilities. Another strength of this core facility is the tight integration with the clinical discovery core and the virology core. The access to clinical specimens through the clinical discovery core, and the wealth of experience in clinical specimen processing by all the core directors, has made clinical specimens available for use by CFAR investigators. This has provided basic scientists at Vanderbilt and Meharry the opportunity to perform translational research. The immunopathogenesis core laboratory also offers training in state of the art immune function assays, and access to BL3 hood space. This allows for rapid preparation of samples, and direct access to the flow sorter and microscopy station. The objectives of this CFAR core laboratory are to provide immunology-related services and support to all CFAR investigators. These specific aims include: 1. To provide high-quality sorting of biohazardous cells and flow cytometry to CFAR investigators. 2. To provide expertise, consultation, assay performance, and training in immunology techniques including those that require BL3 procedures. 3. To provide unique cellular imaging capabilities to CFAR investigators: 4. To aid in processing and storage of PBMC for CFAR investigators: Our recent implementation of leukapheresis of HIV-infected subjects for targeted cohort studies will ensure access to samples by several investigators. 5. To stimulate collaborations on HIV immunopathogenesis among Vanderbilt and Meharry investigators. The immunopathogenesis core laboratory has already fostered new interactions between D-CFAR members, and will further enhance collaboration with this proposal.